This application is related to a copending U.S. application Ser. No. 68,735 filed on Aug. 22, 1979, now U.S. Pat. No. 4,245,594, and assigned to the same assignee of this application.
This invention relates to an ignition device and, more particularly, to an ignition device of the AC continuous discharge type for restricting the primary coil current of an ignition coil.
A conventional ignition device for an ignition-type internal combustion engine, having an ignition coil and a breaker, has been constructed on the basis of a principle that magnetic energy previously stored in an ignition coil is supplied to an ignition plug (spark plug) through the secondary coil when the breaker opens. In one combustion stroke of the internal combustion engine, a discharge duration ranges 1 to 2 msec and an average discharge current ranges 20 to 30 mA. Either when the air-fuel mixture is leaned or when the engine is operated in an exhaust gas recirculation (EGR) mode, the conventional device encounters problems of insufficient ignition, deterioration of fuel consumption of the engine, and a large amount of harmful components in exhaust gases.